S/V70 has different trailing arms to c70, same part number

Post by **smacknab** » 25 Aug 2020, 15:46

Hi friends,

Just posting this info up for future searches. I broke the lower shock stud on my 1999 2wd s70 and decided to swap in a junk yard complete trailing arm. The trailing arms off a 2000 c70 happened to be the least crusty so I swapped that in. Before I did I checked the Volvopartswebstore diagrams and the trailing arms are listed as the same part number so I figured I'd be good. Turns out they're a little wider, increasing the rear track width by 2inches.

I looked more into it and thecarconnection.com lists the track widths for the s70 and c70 as (front/rear) 59.8/57.8in and 59.8/59.8, respectively. Links below for anyone who is curious. I read up a little on the effects of symmetrical/asymmetrical track widths and from what I understand a narrower rear track width increases turning radius on tighter corners and somehow effects over- or under- steer. I'll let those more knowledgeable elaborate if they want to.

I checked some other forums and it seems people have done this swap intentionally for Stance/aesthetic reasons. And I won't lie, I do think it looks better, but that's my opinion. This was such a big job that I won't be looking for an original s/v70 trailing arm assembly to put back in, so I'll follow up with any noticable differences for those who are interested.

Please note my car in the photos hasn't been aligned yet so that's why the wheel looks skewed.

https://www.thecarconnection.com/specif ... o_s70_1999
https://www.thecarconnection.com/specif ... o_c70_2000

Post by **smacknab** » 27 Aug 2020, 08:24

Update: looks like the rear wheels are now rubbing on the edge of the tire over bumps and sharp transitions to inclines, due to the extra track width. I looked into it and spoke with a guy who did this intentionally to an 850 and he said he had to roll the fenders. I'm only running 15inch wheels so it seems like it'll happen at any time size. I'm gonna roll the fenders and see what happens, maybe post some photos.

For changes to driving- the car doesn't turn as tight at lower speeds, but feels more planted at higher speed road bends. That's obviously my subjective take, but makes sense based on the rear track width change.

Post by **abscate** » 27 Aug 2020, 08:30

Understeer is a significant problem as you idle along in route 93 traffic at 3mph.

Post by **smacknab** » 28 Aug 2020, 14:49

I found the difference between the two, seems like they added the inch to each side between the spindle/brake bracket and the end of the trailing arm, basically extended the hub out. If you look at the two photos you'll see how they did it. Top photo is the c70 unit on my car, bottom photo is the original.

I can confirm that rolling fenders is necessary, I couldnt find anyone who could do it anytime soon for less than $150 so I just hammered the suckers up a little bit. I have to do some fender painting anyway so I didn't mind. I'm only running 15in wheels so the rub was minimal, meaning it didn't need a full on roll.

Post by **abscate** » 28 Aug 2020, 18:05

You can see where they welded in that plate when they make the trailing arm

My guess is the c70 version is NLA and they have superseded it with the S/V70 part numbers, which are

.........right

..........left

Bmdub, I can smell your judging our rusty cars all the way up here in NY. Go breathe in some Tar Heel.

( luvya, man)

Post by **abscate** » 28 Aug 2020, 18:13

Good shot of my v70 skinny trailing arms in this thread

viewtopic.php?p=461775#p461775

Post by **smacknab** » 28 Aug 2020, 18:32

abscate wrote: ↑28 Aug 2020, 18:05 Bmdub, I can smell your judging our rusty cars all the way up here in NY. Go breathe in some Tar Heel.

( luvya, man)

Lol yeah the least crusty set I could fine is still pretty bad

Post by **smacknab** » 31 Aug 2020, 20:52

Another update - the rubbing came back with two people in the back so i went back at it with a hammer and heat gun. I also pulled the plastic wheel well covers and cut a couple inches out. The hammering deformed the fender body-line a smidge, so if anyone is planning on doing this swap and wants to keep things clean I'd say either expect to bring it to a shop for a fender roll (I got quoted $120-150) or plan on ordering a fender roller ($60-75 online) ahead of time since i could only find them online with 5-7 business days shipping.